U.S. Pat. No. 6,121,614 discloses an infrared sensor of the above self-contained type having a dielectric support on which the pyroelectric element as well as the IC chips are mounted. The support is held within a space between a base and a cover. The base has I/O pins that are connected to the IC chip and projects for connection with an external circuit. In order to electrically connect the IC chip to the pyroelectric element, external electric parts, and the I/O pins, the support of generally cuboid configuration is formed with a complex conductor pattern extending across two or more outer surfaces of the support. However, the conductor pattern can be only realized through several processes with the use of specific facilities, which makes it difficult to make the sensor at a low cost.